PHP IP Get City API (pure IP database)

/** * Get city name based on IP address pure IP database * edit:bbs.it-home.org */ function Convertip ($IP) { IP Data File path $dat _path = ' QQWry.Dat '; Check IP Address if (!filter_var ($ip, filter_validate_ip)) { Return ' IP address Error '; } Open IP Data file if (! $fd = @fopen ($dat _path, ' RB ')) { Return ' IP date file not exists or access denied '; } Decomposition IP for operation, resulting in shaping number $ipNum = Ip2long ($IP); Get IP Data index start and end locations $DataBegin = Fread ($FD, 4); $DataEnd = Fread ($FD, 4); $ipbegin = Implode (' ', Unpack (' L ', $DataBegin)); if ($ipbegin < 0) $ipbegin + = POW (2, 32); $ipend = Implode (' ', Unpack (' L ', $DataEnd)); if ($ipend < 0) $ipend + = POW (2, 32); $ipAllNum = ($ipend-$ipbegin)/7 + 1; $BeginNum = 0; $EndNum = $ipAllNum; Search for matching IP records from index records using binary lookup while ($ip 1num> $ipNum | | $ip 2num< $ipNum) { $Middle = Intval (($EndNum + $BeginNum)/2); Offset pointer to index position read 4 bytes Fseek ($FD, $ipbegin + 7 * $Middle); $ipData 1 = fread ($FD, 4); if (strlen ($ipData 1) < 4) { Fclose ($FD); Return ' System Error '; } Extracted data transformation growth shaping, if the data is negative, plus 2 of the power of 32 $ip 1num = Implode (', Unpack (' L ', $ipData 1)); if ($ip 1num < 0) $ip 1num + = POW (2, 32); Extract the number of long integers greater than our IP address then modify the end position to the next loop if ($ip 1num > $ipNum) { $EndNum = $Middle; Continue } Remove an index after the last index is taken $DataSeek = Fread ($FD, 3); if (strlen ($DataSeek) < 3) { Fclose ($FD); Return ' System Error '; } $DataSeek = Implode (', Unpack (' L ', $DataSeek. chr (0))); Fseek ($FD, $DataSeek); $ipData 2 = fread ($FD, 4); if (strlen ($ipData 2) < 4) { Fclose ($FD); Return ' System Error '; } $ip 2num = Implode (', Unpack (' L ', $ipData 2)); if ($ip 2num < 0) $ip 2num + = POW (2, 32); No hints found if ($ip 2num < $ipNum) { if ($Middle = = $BeginNum) { Fclose ($FD); Return ' Unknown '; } $BeginNum = $Middle; } } The following code read dizzy, did not read clearly, interested in reading slowly $ipFlag = Fread ($FD, 1); if ($ipFlag = = Chr (1)) { $ipSeek = Fread ($FD, 3); if (strlen ($ipSeek) < 3) { Fclose ($FD); Return ' System Error '; } $ipSeek = Implode (', Unpack (' L ', $ipSeek. chr (0))); Fseek ($FD, $ipSeek); $ipFlag = Fread ($FD, 1); } if ($ipFlag = = Chr (2)) { $AddrSeek = Fread ($FD, 3); if (strlen ($AddrSeek) < 3) { Fclose ($FD); Return ' System Error '; } $ipFlag = Fread ($FD, 1); if ($ipFlag = = Chr (2)) { $AddrSeek 2 = fread ($FD, 3); if (strlen ($AddrSeek 2) < 3) { Fclose ($FD); Return ' System Error '; } $AddrSeek 2 = Implode ("', Unpack (' L ', $AddrSeek 2.chr (0))); Fseek ($FD, $AddrSeek 2); } else { Fseek ($FD,-1, seek_cur); } while ($char = Fread ($FD, 1))! = Chr (0)) $ipAddr 2. = $char; $AddrSeek = Implode (', Unpack (' L ', $AddrSeek. chr (0))); Fseek ($FD, $AddrSeek); while ($char = Fread ($FD, 1))! = Chr (0)) $ipAddr 1. = $char; } else { Fseek ($FD,-1, seek_cur); while ($char = Fread ($FD, 1))! = Chr (0)) $ipAddr 1. = $char; $ipFlag = Fread ($FD, 1); if ($ipFlag = = Chr (2)) { $AddrSeek 2 = fread ($FD, 3); if (strlen ($AddrSeek 2) < 3) { Fclose ($FD); Return ' System Error '; } $AddrSeek 2 = Implode ("', Unpack (' L ', $AddrSeek 2.chr (0))); Fseek ($FD, $AddrSeek 2); } else { Fseek ($FD,-1, seek_cur); } while ($char = Fread ($FD, 1))! = Chr (0)) { $ipAddr 2. = $char; } } Fclose ($FD); The result is returned after the corresponding substitution operation is finally made if (Preg_match ('/http/i ', $ipAddr 2)) { $ipAddr 2 = "; } $IPADDR = "$ipAddr 1 $ipAddr 2"; $IPADDR = preg_replace ('/cz88.net/is ', ' ', $ipaddr); $IPADDR = preg_replace ('/^s*/is ', ' ', $ipaddr); $IPADDR = preg_replace ('/s*$/is ', ' ', $ipaddr); if (Preg_match ('/http/i ', $ipaddr) | | $ipaddr = = ") { $ipaddr = ' Unknown '; } return $ipaddr; } Header ("content-type:text/html; Charset=utf-8 "); $ip = $_server[' http_x_forwarded_for '); if (isset ($_get[' Q '))) { $ip = $_get[' Q ']; if (Filter_var ("http://". $ip, filter_validate_url,filter_flag_host_required)) { $ip = gethostbyname ($IP); } } echo "$ip,". Mb_convert_encoding (Convertip ($IP), "Utf-8", "gb2312"); ?> Copy Code

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